Amyloid β-Protein (25-35) amide

Amyloid β-Protein (25-35) amide is a product of the amidation of amyloid-β (Aβ), in which the ability to generate Aβ is strongly reduced^[1]. Amyloid β-Protein (25-35) amide is a modified fragment sequence of the Aβ peptide, consisting of amino acids 25-35, with the C-terminus blocked by an amide bond^[2]. The amino acid sequence of Aβ (25-35) peptide is NH2-Gly-Ser-Asn-Lys-Gly-Ala-Ile-Ile-Gly-Leu-Met-COOH, where the first Gly represents amino acid 25 and the last Met represents amino acid 35^[3]. Aβ is neurotoxic, but the strength of the toxicity is not related to its aggregation state. Aβ oligomers also show neurotoxicity and cause neuronal damage^{[4, 5]}. Aβ is involved in the pathogenesis of Alzheimer's disease and is present in neurons of the subiculum and entorhinal cortex of Alzheimer's brain samples and inclusion body myositis (IBM) muscles. It binds to receptors present in microglia and is able to insert into lipid membranes^[6].

References:
[1] Li H, Rahimi F, Bitan G. Modulation of amyloid β-protein (Aβ) assembly by homologous C-terminal fragments as a strategy for inhibiting Aβ toxicity[J]. ACS chemical neuroscience, 2016, 7(7): 845-856.
[2] Ghosh N, Kundu L M. Breaker peptides against amyloid-β aggregation: a potential therapeutic strategy for Alzheimer’s disease[J]. Future Medicinal Chemistry, 2021, 13(20): 1767-1794.
[3] Cheung N S, Small D H, Livett B G. An Amyloid Peptide, βA4 25–35, Mimics the Function of Substance P on Modulation of Nicotine‐Evoked Secretion and Desensitization in Cultured Bovine Adrenal Chromaffin Cells[J]. Journal of neurochemistry, 1993, 60(3): 1163-1166.
[4] Aleksis R, Oleskovs F, Jaudzems K, et al. Structural studies of amyloid-β peptides: Unlocking the mechanism of aggregation and the associated toxicity[J]. Biochimie, 2017, 140: 176-192.
[5] Rahimi F, Li H, Sinha S, et al. Modulators of amyloid β-protein (Aβ) self-assembly[M]//Developing Therapeutics for Alzheimer's Disease. Academic Press, 2016: 97-191.
[6] Millucci L, Ghezzi L, Bernardini G, et al. Conformations and biological activities of amyloid beta peptide 25-35[J]. Current Protein and Peptide Science, 2010, 11(1): 54-67.